[Rally-Fast]

So I'm driving down the highway and notice a little high pitched noise coming from the back end- sounds almost like a turbine engine at low rpm. There is no interior trim in my car so it's fairly easy to hear noise from that aspect. Now it's just getting louder, so loud it overtakes the exhaust. So when I get home I jack it up, pull booth wheels off, pull the calipers off, and the rotors, and I can't find any evidence of rubbing. Everything looks OK.

About 2000 mi. ago I had the rear hubs rebuilt, by a reputable shop, with new bearing/seals/wheel studs. Can it possibly be that? Or the rear diff? CV joints? It really seems to come from both sides. Or is something just making it hit natural frequency?

Dear god I'm going insane...

 

[GC8.Love]

Not diff noise, I hope.

"Singing" makes me think of diff noise. :run:

 

[UnderpoweredRS]

I had a rear diff with a bad bearing that did that. would only happen on the highway under certain loads.

It was the forward most bearing the the diff a rear b*tch to do.

 

[Rally-Fast]

So it could be the input side bearing? I geuss that would explain why I think I hear it from both sides.
Ugh.

I wish I had a video camera so I cost post what it sounds like. My camera only takes vid with no audio

 

[Rally-Fast]

whats a good way to check the diff side bearings?

 

[Storm]

Unfortunately, you need to pull the bearing races off the diff case to check them. If it were me, I would ask myself if the wheel bearings got new grease during install? Then I'd ask if the axle nuts were torqued up to spec and not beyond? Finally, I'd pull it all apart and check the diff carrier bearings.

 

[Rally-Fast]

Unfortunately, you need to pull the bearing races off the diff case to check them. If it were me, I would ask myself if the wheel bearings got new grease during install? Then I'd ask if the axle nuts were torqued up to spec and not beyond? Finally, I'd pull it all apart and check the diff carrier bearings.

I am sure they got greased and torqued correctly since I installed the hubs myself. I just had the hubs at the shop to press in the bearings and they put in the new seals ect.

Do I need to remove the whole diff from the subframe, or can I just take out the axles and check that way? I never really messed around with that end of the car much except when I installed the rear skidplate.

Crap, not really what I needed right now since I'm supposed to drive to NNJ tomorrow to flock dashes:curse:

 

[tomahagne]

I guess I'll ask the obvious question: have you asked anyone to ride with you and track down the location of the noise while driving?

To clarify, the sound starts quiet and gets louder as you drive farther. And it repeats the cycle every time you drive.

I heard something similar when I was driving with my back seat panel off to make room for some long boxes. Turned out to just be the fuel pump. But mine wasn't louder than my exhaust. *shrug*

 

[Rally-Fast]

The sound starts as soon as the car is moving. I can coast with the clutch disengaged and is still makes the noise. The higher the speed, the higher the volume. At 60mph it's louder than my scoobysport exhaust with a non-resonated midpipe. I even tried switching tires to see if that would have been it.
It really has no correlation with distance driven; just with actual velocity.

 

[Cinthetyk]

Mine started making noise today. However, it doesn't make a high-pitched or loud noise. It is first noticeable at 35mph and is distinct (sticks out, rather) at 45mph. Is sounds very similar to regular tire noise, but it is only coming from the rear. It didn't sound so much as a turbine as just a medium-pitched hum. The pitch was directly related to vehicle speed, and not engine revolutions.

As far as I am aware, I haven't done anything to the car lately that would have caused this. I glanced around the wheel wells and noticed no rubbing. I had to drive a little on the highway, but got onto the access road when I could. When I have time, I'm going to check the diff fliud.. but no trace of leaking can be seen.

Any thoughts?

 

[kurt.]

If the noise is changing with the speed as described, its probably is the diff in one sense or another.

My advice is:
Drain the fluid and check for metal particles.
Replace with some good fluid and see if that helps at all.

-Kurt

 

[Rally-Fast]

and then check your wheel bearings. They often start like that and get louder.

 

[poormansporsche]

Mine just started doing this a couple days ago. It's a medium hum. Gets louder with speed. Even without the clutch engaged it still makes noise. I hope it's not the diff. The only thing that changed was I had the tires rotated. The front tires were trashed due to a bad alignment. There was lots of wobbling after the tire rotation as the tires were probably out of round. The ass end was shaking for a few hundred miles, it stopped and now it's just this noise.

cheers

poorman

 

[themattcole]

^ from experience, id say it is most likely the rear differential

 

[SIN6AIX651]

Maybe it's coming from your speakers. A friend created some sparks on his amp while screwing a screw with a magnetic screwdriver. After that, when the stereo is on, there's a high pitched whistling that increases with throttle. Mine is doing the same. I'm thinking that it's because I messed up the internal amp in my touchscreen. sound's gone when I reinstalled the oem stereo.

 

[themattcole]

^i have that issue too. but only when on auxillary

 

[Storm]

I'm pretty sure anyone with half a brain would turn the fucking radio off to see if they can hear the noise better and possibly pinpoint it.


I'm also pretty sure that if the noise went away with the radio....this thread wouldn't exist.

 

[Rally-Fast]

I don't even have a radio in my RS anymore. No head unit, no speakers.

POORMAN: Does it sound high pitched or more like a chop chop chop like a small helicopter?

 

[SIN6AIX651]

I'm pretty sure anyone with half a brain would turn the fucking radio off to see if they can hear the noise better and possibly pinpoint it

Some people only have quarter brains.

 

[nme187]

Sorry to bump this thread but I'm scratching my head with this one and praying someone has an answer.

I'm having similar symptoms with my 00 RS that started back in August. Somewhere around the right rear I hear this humming noise only when I'm doning 40+mph. So initially I thought it was the wheel bearing so I went ahead and replaced it but the sound didn't even change note at all. I didn't replace the hub+wheel bearing, just the bearing so I think I might of screwed myself there...

I replaced my rear diff fluid with redline like 2-3months ago assuming that would fix it but that did nothing.

I've spoke with the tech at Subaru and he said a way to tell if it's a wheel bearing is to take a turn with speed (when you can hear the noise) and if it stops or quiets down when doing only left or right turns then it would be a wheel bearing since your testing putting a load on them. Well I just took my car down the road with plenty of speed and the sound didn't change at all....

Only thing holding me back from saying it's the rear diff is that the noise is definately coming from the right rear by the wheel and not the center.

Anyone ever fix theirs?